x86/mce: Make timer handling more robust

Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola <erik.veijola@intel.com>
Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

path: root/crypto.h

#ifndef CRYPTO_H
#define CRYPTO_H

#include "taia.h"
#include "crypto_verify_32.h"
#include "crypto_hash_sha512.h"
#include "crypto_box_curve25519xsalsa20poly1305.h"
#include "crypto_scalarmult_curve25519.h"
#include "crypto_auth_hmacsha512256.h"

#define crypto_box_zerobytes		crypto_box_curve25519xsalsa20poly1305_ZEROBYTES
#define crypto_box_boxzerobytes		crypto_box_curve25519xsalsa20poly1305_BOXZEROBYTES
#define crypto_box_noncebytes		crypto_box_curve25519xsalsa20poly1305_NONCEBYTES
#define crypto_box_beforenmbytes	crypto_box_curve25519xsalsa20poly1305_BEFORENMBYTES
#define crypto_box_beforenm		crypto_box_curve25519xsalsa20poly1305_beforenm
#define crypto_box_afternm		crypto_box_curve25519xsalsa20poly1305_afternm
#define crypto_box_open_afternm		crypto_box_curve25519xsalsa20poly1305_open_afternm
#define crypto_box_pub_key_size		crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES
#define crypto_box_sec_key_size		crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES

#define NONCE_LENGTH			(sizeof(struct taia))
#define NONCE_RND_LENGTH		(crypto_box_boxzerobytes - NONCE_LENGTH)
#define NONCE_ALL_LENGTH		(crypto_box_boxzerobytes + NONCE_LENGTH)
#define NONCE_OFFSET			(crypto_box_noncebytes - NONCE_LENGTH)
#define NONCE_EDN_OFFSET(x)		((x) + NONCE_OFFSET)
#define NONCE_PKT_OFFSET(x)		((x) + NONCE_RND_LENGTH)

#endif /* CRYPTO_H */